#include <iostream>
#include <unordered_map>
using namespace std;
unordered_map<int, int> mp;
int a[110];
int main()
{
    int l, r; cin >> l >> r;
    a[1] = 1;
    a[2] = 0;
    for(int i = 3; i <= 100; i++) a[i] = a[i - 2];
    for(int i = l; i <= r; i++)
    {
        mp[a[i]]++;
    }
    cout << mp.size() << endl;
    return 0;
}